Through the use of central solar heating plants with large, seasonal storage systems, solar energy can be collected during the summer and stored until needed in the heating season when solar radiation is often insufficient. As a result of the Task 7 collaboration, significant advances were made in this technology.

During the first phase, participants collected engineering, performance and cost data on the major component subsytems. A parallel effort involved the development of MINSUN, a simulation and optimization program for central solar heating plants.

In the second phase, MINSUN was used to make a systematic evaluation of various design concepts and to identify thise which appeared to be modt promising. During phase III, participants exchanged data on the design, construction and operation of existing or new CSHPSS systems and jointly evaluated this information.


The main aim of the CSHPSS Working Group is to enhance the development of large-scale solar heating technologies (i.e. residential heating, district heating, process heating at moderate temperatures) through knowledge transfer on both general and more specific issues (e.g. design of new plants), between participating countries.


A series of workshops concerning large-scale solar heating applications. The workshops should be organised annually (at least) in connection to a demonstration project and be open for all IEA countries in order to create a common forum for expert groups working with Central Solar Heating Plants (or CSHP), and form the base for continued international co-operation.


The working group commenced when a proposed task was postponed. The duration depends on the interest among participating experts and ExCo members. The ongoing co-operation agreement ends in October 1995.


The activity since the last ExCo meeting comprises a workshop "1995 Workshop on CSHPSS Design" in Stuttgart, Germany, March 9 - 11, 1995. The workshop was organised with a one day design review of the Friedrichshafen-Wiggenhausen and Hamburg-Bramfeld projects and one day presentations and discussions related to existing and future water storage designs together with short presentations of some new CSHP projects.

The last day of the workshop was arranged as a study tour to the Rottweil pilot storage (water storage, concrete tank, stainless steel liner, 600m³), the building site for the Friedrichshafen-Wiggenhausen project and the Ravensburg projects (two CSHPDS systems with roof-integrated collectors).

The workshop was attended by 17 participants from Germany, 6 from Sweden, 5 each from Denmark and Austria, 2 from the Netherlands, and 1 each from Switzerland, Finland and Italy, including 4 ExCo members (Germany, Sweden, Austria and Finland), which makes a total of 38 participants.


  • Proceedings 1994 Workshop on Large-scale Solar Heating
    Dalenbäck, J-O. Ed. (1994). CIT Energiteknisk Analys, Göteborg. 
    Report no. 1994:1
  • Notes from 1995 Workshop on CSHPSS Design
    Dalenbäck, J-O. Ed. (1995). Dated April 17, 1995. 
    Building Services Engineering, Chalmers University of Technology, Göteborg


The activities of the CSHPSS Working Group are scheduled to comprise two workshops during 1995, one in connection with the final design phase of a demonstration project, and the other a general workshop similar to the previous 1994 Workshop on Large-scale Solar Heating held in Göteborg, August 1994.

The review workshop was arranged in Stuttgart, March 1995 (see Activity), and Austria has volunteered to host the 1995 Workshop on Large-scale Solar Heating in Vienna, early October 1995.


Sweden has agreed to prolong the leadership for the CSHPSS Working Group from November 1, 1993, to October 31, 1995, and undersigned has been appointed, by the Swedish ExCo members, Michael Rantil at Swedish Council for Building Research to organise the approved technical workshops and propose a continuation at the next ExCo meeting in Stockholm, October 1995.


  • Establishing the feasibility and cost-effectiveness of CSHPSS
  • Design tool development
  • Evaluation of design concepts
  • Performance measurement and evaluation


  • CSHP Central Solar Heating Plant
  • CSHPSS Central Solar Heating Plant with Seasonal Storage
  • CSHPDS Central Solar Heating Plant with Diurnal Storage
  • CSHPxS Central Solar Heating Plant without Storage
    ( connection to a district heating network)